Cytogenetic Effects in Patients after Computed Tomography Examination.

Millions of people around the world are exposed to low doses of ionizing radiation from diagnostic computed tomography (CT) scans. Currently available data on the potential cancer risk after CT scans are contradictory and therefore demand further investigations. The aim of the current study was to obtain estimations of genome damage after CT scans in 42 non-cancer patients and to conduct a comparison of the results with 22 control subjects.

Construction of Calibration Curve for Premature Chromosome Condensation Assay for Dose Assessment.

Cytogenetic dosimetry plays an important role in the triage and medical management of affected people in radiological incidents/accidents. Cytogenetic biodosimetry uses different methods to estimate the absorbed dose in the exposed individuals, and each approach has its advantages and disadvantages. Premature chromosome condensation (PCC) assay presents several advantages that hopefully fulfill the gaps identified in the other cytogenetic methods.

Follow-up studies on genome damage in children after Chernobyl nuclear power plant accident.

As children are more susceptible to ionizing radiation than adults, each nuclear accident demands special attention and care of this vulnerable population. The Chernobyl nuclear disaster occurred in a region populated with a large number of children, but despite all efforts and expertise of nuclear specialists, it was not possible to avoid casualties. As vast regions of Ukraine, Belarus and Russia were exposed to doses of ionizing radiation, which are known to be related with different diseases, shortly after the accident medical surveillance was launched, which also included analysis of genome damage.

[THE INFLUENCE OF THE PREPARATION PRETREATMENT ON IN SITU DETECTION OF 5-METHYLCYTOSINE IN METAPHASE CHROMOSOMES AND IN INTERPHASE NUCLEI].

Qualitative and quantitate analysis of DNA methylation in situ at the level of cells, chromosomes and chromosomal domains is extremely important for the diagnosis and treatment of various diseases, the study of ageing and the consequences of environmental impacts. An important question arises, whether the revealed in situ methylation pattern reflects DNA methylation per se and (or) availability of the DNA for antibodies, which in turn depends on the peculiarities of chromatin structure and chromosome condensation. These events can lead to an incorrect evaluation of the actual pattern of DNA methylation.

[Comparative analysis of cytogenetic examination of control groups of subjects carried out in different Russian laboratories].

The incidence of unstable chromosome aberrations in peripheral blood lymphocytes from unirradiated control subjects was analyzed using cytogenetic data obtained from 9 cytogenetic laboratories located in Moscow, St.-Petersburg, Obninsk, and Dubna (Russia). The objective of this study was to estimate the level and spectrum of spontaneous chromosome aberrations in human lymphocytes.

Chromosomal aberrations and sickness rates in Chernobyl clean-up workers in the years following the accident.

The aim of this investigation was to reveal a possible correlation between chromosomal aberrations and the health status of Chernobyl clean-up workers who suffered from a low dose of ionizing radiation. Unstable chromosomal aberrations in peripheral blood lymphocytes were investigated in 491 Chernobyl clean-up workers. Information about lifestyle factors (all persons) and medical history (212 persons) was collected.

Cytogenetic study of professional rescue rangers of Russian Ministry of Emergencies.

Cytogenetic studies in rescue rangers of the Russian Ministry of Emergencies has shown that this category of specialists are exposed to genotoxic factors during their professional activity. The level of induction of cytogenetic injuries of rescue team members depended on labor conditions, genotype (glutathione-S-transferase M1 and T1 xenobiotic detoxication genes), and tobacco smoking.

[Chromosomal aberrations and parameters of oxidative stress in Chernobyl clean-up workers in a remote period after ionizing radiation].

This investigation was performed to test a supposition about the influence of disturbances in antioxidative system on cytogenetical parameters in Chernobyl' clean-up workers. It was shown that some cytogenetical parameters straightly correlated with the parameters of oxidative stress, while other cytogenetical parameters show just reverse correlations. Apparently, these relationships are not of cause-and-effect type, but they reflect a complex processes occurring in humans for a long period after radiation exposure.

Chromosome alterations in cleanup workers sampled years after the Chernobyl accident.

Cytogenetic analysis performed 4-13 years after the Chernobyl accident showed an elevated frequency of acentrics, chromatid exchanges, dicentrics and rings in Chernobyl cleanup workers compared to the control group. Cytogenetic data were analyzed according to the information on exposure to radiation (the year when the cleanup workers worked at the Chernobyl station, doses rates, time elapsed since exposure to radiation, and cytogenetic examination) and some lifestyle factors. The data obtained suggested that some types of chromosome aberrations could be influenced by the action of different environmental factors or lifestyle factors.

[Some complexities in evaluating radiation-induced mutagenic effects in man].

Chromosomal aberrations in somatic cells (circulating lymphocytes) have been investigated in a remote period in different groups of people who suffered from radiation accidents. The chromosomal radiation markers were found even decades after irradiation. The question about the necessity of registration of non-classical mutagenic effects after human irradiation is raised.

Persistence of dicentrics in Chernobyl clean-up workers who suffered from low doses of radiation.

Blood samples from 243 clean-up workers who undertook duties at Chernobyl in 1986 were examined in order to study temporal changes of chromosomal aberrations over long periods (6-12 yr) following irradiation. From an analysis of the elapsed time between irradiation and cytogenetic examination, it was found that the frequency of dicentrics and rings did not decrease during the 6 yr period of observation.

Cytogenetic investigation of occupationally irradiated persons a long time after exposure.

Chromosomal analyses were performed in blood lymphocytes of 33 persons previously occupationally exposed to ionizing radiation. An increased frequency of chromosome aberrations, mainly dicentrics, a long time, up to 47 years after exposure, suggests that it is possible to use the method of unstable aberration analysis for assessment of previous radiation exposure. The enhanced yield of dicentrics was observed in persons who may have received irradiations above permitted limits.

Cytogenetic investigation of thallium-poisoned people: pilot study.

Thirteen blood samples of thallium-poisoned people were cytogenetically investigated. The thallium concentration in blood varied from 25 to 2700 microg/L. The mean frequency of chromosomal aberrations in the poisoned group significantly exceeded our control level (7.

Increased level of chromosomal aberrations in lymphocytes of Chernobyl liquidators 6-10 years after the accident.

Chromosomal aberrations (CA) were used to investigate the level of cytogenetical damage in peripheral blood lymphocytes from the liquidators in a remote period (6-10 years) after the Chernobyl accident. There was a significantly higher frequency of chromosomal radiation markers (dicentrics and rings) in the peripheral lymphocytes of the liquidators than in the control subjects. No differences between these groups were demonstrated by the micronucleus (MN) test.

[Chromosomal anomalies of human gametes and intrauterine selection. Research on female gametes].

The results of cytogenetical analysis of human oocytes are summarized. The chromosomal disorders in human gametes and in spontaneous abortions are comparatively analyzed.

[Chromosome abnormalities of human gametes and intrauterine selection. Male gametes].

Man appears to be unique among mammals with respect to very high level of reproductive wastage. It seems reasonable to suppose that many early losses attribute to cytogenetical abnormalities. However, this stage of pregnancy is difficult to be studied.

[Chromosomal disorders in the oocytes of rats after stress exposure in the preovulatory period].

Female rats at the stage of proestrus have been subjected to a stress effect--immobilization for an hour. Oocytes were cytogenetically analyzed and embryonal mortality was determined. It is shown that this stress effect at the end of the fist meiotic division of the oocytes increased the rate of aneuploid gametes and the level of embryonal mortality.

[Variants of chromosome compactization and the estimation of the capacity of mammalian oocytes for further development].

The morphology of chromatin in spontaneously ovulated rat's oocytes was investigated. The degree of chromatin condensation was shown to vary widely: along with the typical cytological picture of metaphase II, both highly condensed (clamped) and decondensed ("not typical") forms of chromosomes were observed. A direct relation was discovered between the prevalence of the not typical morphological forms of oocyte chromosomes and the level of embryonal death.